1. Field of the Invention
The invention relates to an electromechanical locking mechanism for door leaves which are fitted with a closing means more specifically in the form of a door closing device. The closing shaft of the door closing device is connected to one end of a pivot arm and the other end of the pivot arm is displaceable in the longitudinal direction by way of a slider in a guide rail. The slider co-operates with a locking mechanism which fixes the door leaf in a predetermined open position. In the event of any dangerous situation, such as for example a fire, a detector generally releases the lock on the door leaf, so that the door leaf can move reliably into the closed position by virtue of the energy stored in the spring-loading device of the door closing device.
2. Background Information
An electric locking mechanism for door leaves is disclosed in U.S. Pat. No. 3,771,823. A guide roller, which is connected by way of an actuating arm to the door closing device attached to the door, is located within a guide rail. Above the guide tracks for the sliding rollers, a further guide track is provided in the guide rail, in which further guide track a retaining member, connected directly to the roller located below, can be displaced likewise in a longitudinal direction within the rail. In addition thereto, provided in the guide rail is a recess at which the locking mechanism is mounted on a fixed fixing point. The locking mechanism consists in particular of a solenoid and attached to the armature of said solenoid is a push rod which is designed in such a manner that it penetrates between the two fixed claws, which it pivots in the outwards direction. This can, however, only happen if the retaining device of the slider is moved with its projections into the final position of the door and simultaneously the solenoid is energized. Consequently, the door is held in this position until a sensor signal for example causes the locking action of the magnet to be cancelled and thus the slider is released again. Owing to the type of construction involved, this guide rail is structurally extremely tall, as two chambers are provided in which on the one hand the sliding roller and on the other hand the retaining device can move separately from each other yet above each other mutually connected in the longitudinal direction. Moreover, it is also necessary for this type of locking operation to provide a holding piece in addition to the sliding roller. The retaining force cannot be adjusted.
A locking mechanism for door leaves is likewise disclosed in a further U.S. Pat. No. 5,072,973. The disadvantages, which are described in the case of the aforementioned locking mechanism, have likewise not been eliminated, as guide rails are also used which are structurally extremely tall and are provided with different guide chambers. In addition thereto, a motor is used to lock the door leaf and attached to the axle of the said motor is a spindle which can displace a retaining mechanism in the longitudinal direction in such a manner that the retaining projections located on the slider are held by two retaining arms.